Análisis de levantamiento en estructuras con aisladores de péndulo friccional: parámetros de interés, estimación de magnitudes críticas y medidas de mitigación
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Date
2023
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Abstract
Los sistemas de aislamiento sísmico han sido una herramienta crucial para controlar la respuesta de las estructuras y mejorar su desempeño. En particular, los sistemas friccionales como los péndulos friccionales (FPS) son utilizados en diversas estructuras para aumentar el período fundamental y asé disminuir respuestas de drift, desplazamientos y esfuerzos internos, entre otras. Un problema que presentan estos dispositivos y que puede disminuir su eficacia corresponde al levantamiento de su parte superior y posterior impacto, producido por un volcamiento parcial de parte de la superestructura. Este fenómeno puede producir que la estructura se desestabilice por una falla en los dispositivos de aislamiento, además de aumentar las magnitudes de diversas respuestas como aceleraciones ´ de piso y esfuerzos internos tanto en los elementos estructurales como en los aisladores. Esta tesis plantea un análisis paramétrico de las estructuras aisladas que presentan levantamiento, definiendo los parámetros que las caracterizan. Además, se estudian los efectos ´ que estos levantamientos e impactos verticales tienen en la superestructura. A partir de esto, se analizan las consecuencias de un dispositivo de tipo FPS modificado resiliente a impacto (IR-FPS) en las magnitudes de los levantamientos y en las respuestas de la superestructura. Se observa que dicho dispositivo permite disminuir los levantamientos, y mejorar el comportamiento frente a este fenómeno. Finalmente, se propone una metodología simplificada para estimar las magnitudes de levantamiento y tiempos de levantamiento de las estructuras a partir de un análisis lineal, lo que es de utilidad en las etapas de diseño.
Seismic isolation systems have been a crucial tool to control the response of structures and improve their performance. In particular, frictional systems like Friction Pendulum Systems (FPS) are used in various structures to increase the fundamental period and reduce responses such as drift, displacements, and internal forces, among others. One issue with these devices that can reduce their effectiveness is the uplift of their upper part and subsequent impact, caused by partial overturning of part of the superstructure. This phenomenon can lead to the destabilization of the structure due to failure in the isolation devices, as well as an increase in various responses such as floor accelerations and internal forces in both structural elements and isolators. This thesis presents a parametric analysis of isolated structures experiencing uplift, defining the parameters that characterize them. Additionally, the effects of these uplifts and vertical impacts on the superstructure are studied. Based on this, the consequences of a modified Friction Pendulum System resilient to impact (IR-FPS) device are analyzed regarding uplift magnitudes and superstructure responses. It is observed that this device helps reduce uplift and improves the behavior in response to this phenomenon. Finally, a simplified methodology is proposed to estimate uplift magnitudes and uplift times of the structures using linear analysis, which is useful during the design stages
Seismic isolation systems have been a crucial tool to control the response of structures and improve their performance. In particular, frictional systems like Friction Pendulum Systems (FPS) are used in various structures to increase the fundamental period and reduce responses such as drift, displacements, and internal forces, among others. One issue with these devices that can reduce their effectiveness is the uplift of their upper part and subsequent impact, caused by partial overturning of part of the superstructure. This phenomenon can lead to the destabilization of the structure due to failure in the isolation devices, as well as an increase in various responses such as floor accelerations and internal forces in both structural elements and isolators. This thesis presents a parametric analysis of isolated structures experiencing uplift, defining the parameters that characterize them. Additionally, the effects of these uplifts and vertical impacts on the superstructure are studied. Based on this, the consequences of a modified Friction Pendulum System resilient to impact (IR-FPS) device are analyzed regarding uplift magnitudes and superstructure responses. It is observed that this device helps reduce uplift and improves the behavior in response to this phenomenon. Finally, a simplified methodology is proposed to estimate uplift magnitudes and uplift times of the structures using linear analysis, which is useful during the design stages
Description
Tesis (Magíster en Ciencias de la Ingeniería)--Pontificia Universidad Católica de Chile, 2023
Keywords
Aislamiento sísmico, Levantamiento, Impacto, IR-FPS, Seismic isolation, Uplift, Impact, IR-FPS